Process for manufacturing copper conduits for air conditioning systems with improved anti-corrosive performance

Abstract

A continuous process for producing an air conditioning conduit is provided. The continuous process involves unwinding a copper tube from at least one coil and straightening the copper tube, cleaning the copper tube by plasma treatment, heating the copper tube to complete the cleaning of the copper tube, applying at least one adhesive on an outer surface of the copper tube, applying at least one polyamide anti-corrosion barrier layer over the at least one adhesive, cooling the copper tube coated with the at least one adhesive and the at least one polyamide anti-corrosion barrier layer, and applying around the coated and cooled copper tube at least one insulation layer made of closed-cell insulation material, thus obtaining the air conditioning conduit. The continuous process has the advantages of producing an air conditioning conduit that counteracts the phenomenon of formicary corrosion.

What is claimed is: 
     
         1 . A continuous process for producing an air conditioning conduit, comprising steps of:
 unwinding a copper tube from at least one coil and straightening the copper tube;   cleaning said copper tube by plasma treatment;   heating said copper tube to complete the cleaning of the copper tube;   applying at least one adhesive on an outer surface of said copper tube;   applying at least one polyamide anti-corrosion barrier layer over the at least one adhesive;   cooling said copper tube coated with the at least one adhesive and the at least one polyamide anti-corrosion barrier layer; and   applying around the coated and cooled copper tube at least one insulation layer made of closed-cell insulation material, thus obtaining the air conditioning conduit.   
     
     
         2 . The continuous process of  claim 1 , wherein the at least one adhesive is a homopolymer polyolefin or copolymer functionalized with maleic anhydride. 
     
     
         3 . The continuous process of  claim 2 , wherein the homopolymer polyolefin or copolymer is selected from: polyethylene, medium-density polyethylene copolymer, high-density polyethylene, linear low-density polyethylene, comonomer of C 4 -C 8 , or mixtures thereof. 
     
     
         4 . The continuous process of  claim 1 , wherein the at least one polyamide anti-corrosion barrier layer is a polyamide 12 anti-corrosion barrier layer. 
     
     
         5 . The continuous process of  claim 1 , wherein the at least one adhesive and/or the at least one polyamide anti-corrosion barrier layer comprise at least one additive. 
     
     
         6 . The continuous process of  claim 1 , wherein
 the step of applying the at least one adhesive on the outer surface of said copper tube; and   the step of applying the at least one polyamide anti-corrosion barrier layer over the adhesive   occur simultaneously, by simultaneously applying the at least one adhesive and the at least one polyamide anti-corrosion barrier layer.   
     
     
         7 . The continuous process of  claim 1 , wherein the cleaning step by plasma treatment takes place at a capacity comprised between 2000 VA and 3000 VA and at a frequency comprised between 20 kHz and 35 kHz. 
     
     
         8 . The continuous process of  claim 1 , wherein the heating step takes place at a temperature comprised between 120° C. and 300° C. 
     
     
         9 . An air conditioning conduit obtainable by carrying out the process of  claim 1 , the air conditioning conduit comprising a copper tube coated with at least one adhesive, at least one polyamide anti-corrosion barrier layer, and at least one insulation layer of closed-cell insulation material. 
     
     
         10 . The air conditioning conduit of  claim 9 , wherein said copper tube has an outer diameter comprised between 6.35 mm and 28.60 mm, said at least one adhesive has a thickness comprised between 0.025 mm and 0.080 mm, said at least one polyamide anti-corrosion barrier layer has a thickness comprised between 0.10 mm and 0.60 mm, and said at least one insulation layer of closed-cell insulation material has a thickness comprised between 6 mm and 25 mm. 
     
     
         11 . The continuous process of  claim 8 , wherein the heating step takes place at a temperature comprised between 150° C. and 250° C.